During the last decades there has been a substantial global increase in the amount of CO2 emission to the atmosphere. Emissions of CO2 into the atmosphere are thought to be harmful due to its “greenhouse gas” property, contributing to global warming. Following the Kyoto agreement, CO2 emission has to be reduced in order to prevent or counteract unwanted changes in climate. The largest sources of CO2 emission are combustion of fossil fuels, for example coal or natural gas, for electricity generation and the use of petroleum products as a transportation and heating fuel. These processes result in the production of gases comprising CO2. Thus, removal of at least part of the CO2 prior to emission of these gases into the atmosphere is desirable.
Processes for removal of CO2 are known in the art.
For example, in WO 2006/022885, a process for removal of CO2 from combustion gases is described, wherein an ammoniated slurry or solution is used. One disadvantage of the process described in WO 2006/022885 is that a volatile solvent, ammonia, is used. This will inevitably results in solvent losses. Another disadvantage is that the solvent needs to be cooled to relatively low temperatures, requiring cooling duty.
WO 2006/134225 describes a method and an apparatus for recovering CO2 from flue gases, in which method the flue gases are washed with an alkali metal carbonate containing washing solution in a scrubber. The alkali metal bicarbonate concentration of the solution is increased to such a high level that crystalline alkali metal bicarbonate containing alkali metal bicarbonate slurry is formed.
Non-prepublished WO 2008/072979 describes a method for capturing CO2 form exhaust gas in an absorber, wherein the CO2 containing gas is passed through an aqueous absorbent slurry comprising an inorganic alkali carbonate, bicarbonate and at least one of an absorption promoter and a catalyst, wherein the CO2 is converted to solids by precipitation in the absorber. The slurry is conveyed to a separating device in which the solids are separated off.
There remains a need for a simple, energy-efficient process for removal of CO2 from gases.